问题 选择题

将两只灯泡分别接在甲、乙两个电路中,比较串、并联电路的特点.以下实验现象不可能的是  

                                                

A.在甲电路中,当L1和L2都发光时,取下L1后,L2会熄灭

B.在甲电路中再串联一个小灯泡,接通电路后,L1和L2变暗

C.在乙电路中,当L1和L2都发光时,取下L1后,L2不会熄灭

D.在乙电路中再并联一个小灯泡,接通电路后,L1和L2变亮

答案

答案:D

题目分析:如图所示,甲图是串联电路,乙图是并联电路;串联电路中用电器相互影响,不能独立工作,取下L1后,L2会熄灭,A正确;并联电路中各用电器工作时不互相影响,能够独立工作,取下L1后,L2不会熄灭,C正确;在甲电路中再串联一个小灯泡,总电阻增大,根据,电路中电流减小,根据,两灯泡的电阻不变,电流变小,所以实际电功率变小,所以L1和L2变暗,B正确;在乙图中并联一个小灯泡,L1和L2两条支路,两端电压不变,电阻不变,根据,实际电功率不变,所以灯泡的亮度不变,选D。

点评:解决本题的关键是熟知串并联电路的电流特点,以及知道决定灯泡亮与暗是实际电功率。

单项选择题 A1/A2型题
阅读理解

In 1991, Kentucky Fried Chicken announced that it was officially changing its name to “KFC” as well as updating its packaging and logo(标识)with a more modern look. The public relations reason was that health-conscious consumers associated the word “fried” with “unhealthy”, causing some of them to completely avoid the wide variety of “healthy” menu items. The new title and image were designed to attract customers to a restaurant now offering foods branded as “better for you”.

It sounded good, but the real reason behind the shift to KFC had nothing to do with critical consumers. In 1990, the Commonwealth of Kentucky, trapped in debt, took the unusual step of trade marking its name. Therefore, anyone using the word “Kentucky” for business reasons would have to obtain permission and pay licensing fees to the Commonwealth of Kentucky. It was an unusual and brilliant scheme to lighten government debt, but it was also one that alienated (疏远)one of the most famous companies ever associated with Kentucky. The Kentucky Fried Chicken chain refused as a matter of principle to pay royalties on a name they had been using for four decades. After a year of fruitless talks, Kentucky Fried Chicken changed their name instead, introducing new packaging and products to hide the real reasons behind the change of the name.

Kentucky fried Chicken was not the only one who bravely refused to give in. The name of the most famous horse race in North America, held every year at Churchill Downs, was changed to “The Run for the Roses” for similar reasons.

In November 2006, KFC and the State of Kentucky finally reached a settlement over the use of the trademarked word “Kentucky”, and the restaurant chain announced it would be reusing its former name of “Kentucky Fried Chicken”.

小题1:The public relations reason for Kentucky Fried Chicken’s updating its packaging and logo was that      .

A.it was losing money

B.most customers didn’t like the old logo

C.it wanted to get involved in other businesses

D.it decided to offer better foods to customers小题2:The Commonwealth of Kentucky trademarked its name to       .

A.develop American culture

B.be alienated from the famous companies

C.raise money to pay the government debt

D.make Kentucky known throughout the world小题3:The real reason why “Kentucky Fried Chicken” changed its name was related to      .

A.health

B.money

C.package

D.product小题4:It can be inferred from the passage that      .

A.KFC is still not allowed to use the name of “Kentucky Fried Chicken”

B.“Kentucky Fried Chicken” changed its name after several years of talks

C.the name “Kentucky Fried Chicken” had only been used for a short time

D.the original name of the horse race “The Run for the Roses” contained the word “Kentucky”